JP3616151B2 - Unvulcanized rubber member for pneumatic tire and method for producing the same - Google Patents
Unvulcanized rubber member for pneumatic tire and method for producing the same Download PDFInfo
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- JP3616151B2 JP3616151B2 JP01238395A JP1238395A JP3616151B2 JP 3616151 B2 JP3616151 B2 JP 3616151B2 JP 01238395 A JP01238395 A JP 01238395A JP 1238395 A JP1238395 A JP 1238395A JP 3616151 B2 JP3616151 B2 JP 3616151B2
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- 229920001971 elastomer Polymers 0.000 title claims description 117
- 239000005060 rubber Substances 0.000 title claims description 117
- 238000004519 manufacturing process Methods 0.000 title claims description 16
- 238000001125 extrusion Methods 0.000 claims description 22
- 239000000463 material Substances 0.000 claims description 19
- 239000000203 mixture Substances 0.000 claims description 12
- 238000000465 moulding Methods 0.000 claims description 7
- 241001441571 Hiodontidae Species 0.000 claims description 5
- 150000001875 compounds Chemical class 0.000 claims description 5
- 238000002156 mixing Methods 0.000 claims 1
- 239000011324 bead Substances 0.000 description 31
- 239000000945 filler Substances 0.000 description 9
- 238000013329 compounding Methods 0.000 description 7
- 230000003014 reinforcing effect Effects 0.000 description 6
- 239000002131 composite material Substances 0.000 description 4
- 230000009977 dual effect Effects 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000011156 evaluation Methods 0.000 description 4
- 238000005520 cutting process Methods 0.000 description 3
- 230000007547 defect Effects 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 230000002950 deficient Effects 0.000 description 2
- 230000002093 peripheral effect Effects 0.000 description 2
- 238000004073 vulcanization Methods 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 239000002440 industrial waste Substances 0.000 description 1
- 238000004898 kneading Methods 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 239000003351 stiffener Substances 0.000 description 1
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- Extrusion Moulding Of Plastics Or The Like (AREA)
- Tyre Moulding (AREA)
Description
【０００１】
【産業上の利用分野】
この発明は、空気入りタイヤに適用する押出し未加硫ゴム部材及びその製造方法に関し、特に該ゴム部材の不具合に基づく空気入りタイヤの製造過程における製造不良による製品タイヤのスクラップ発生の抑制と、スクラップ化による産業廃棄物の削減とに有効な空気入りタイヤ用未加硫ゴム部材及びその製造方法に関する。
【０００２】
【従来の技術】
空気入りタイヤの各種組立て部材のうち未加硫ゴム部材はカレンダロールなどのロールにより圧延した一様なゲージをもつシート部材と、押出機による押出し部材とに大別できる。これらのうち後者のゴム部材は概して幅方向にゲージが変化し厚ゲージ領域と薄ゲージ領域ともいうべき２領域に分かれる。
【０００３】
特に空気入りタイヤのうちラジアルプライタイヤの場合、ビード部に所望の剛性を付与するため、ビードコアからタイヤ半径方向外側に向け先細りで延びるビードフィラゴム又はスティフナゴムと呼ばれる断面がほぼ三角形状をなすビード部補強ゴム部材を適用するのが通例である。
【０００４】
この補強ゴム部材は同一配合組成になるゴム材料の単一体の場合と、異種配合組成になるゴム材料の複合体の場合とがタイヤ種により、また要求特性により使い分けられているが、何れの場合も押出機による押出し成形による未加硫ゴム部材として準備するのが慣例である。
【０００５】
【発明が解決しようとする課題】
上記の補強ゴム部材が同一配合組成になるゴム材料の単一体の場合、又は複合体のうち同一配合組成ゴム材料の場合でも、断面積、すなわち適用する押出機の押出し容量を上回る場合は、いわゆる複合形押出機（デュアルチューバ）により押出し成形することも稀には行われるものの、シングルチューバで押出し成形するのが通常である。以下、説明の都合上補強ゴム部材が同一配合組成になる場合に付き述べる。
【０００６】
生産の都合上、つまりタイヤ成形の生産性を可能な限り高めるため、タイヤ成形工程前の準備工程にて、図２（ａ）に断面を示すように押出し成形したビード部補強未加硫ゴム部材１１をビードコア７に予め張合せておくことが必要である。
【０００７】
一方ゴム部材１１は必要長さの一本毎の押出し成形によるものではなく極めて多数本に相当する量を連続して押出し成形するものであり、よって押出し直後に所定長さに順次切断して得られる。この切断時には当然ながら両端切断面が互いに平行な表面を形成している。
【０００８】
このゴム部材１１の厚ゲージ領域側の端面をビードコア７の外周面に張合せると、本来なら図２（ａ）に示すような状態が得られる筈であるところ、実際には同様断面を示す図２（ｂ）に見られるようにゴム部材１１′の先端部分が収縮して内方に向け倒れ込む現象が生じる。この状態のゴム部材１１′をもつビードコア７をタイヤ成形時に適用して未加硫タイヤを仕上げ、これを加硫成形するとゴム部材１１′の先端部分に相当する箇所にエア入りの不良品が発生することを突き止めた。
【０００９】
従ってこの発明の目的は、上記倒れ込みを他の不具合を伴うことなく有利に改善して、エア入りなどのタイヤ製造不良発生を回避することができる空気入りタイヤ用未加硫ゴム部材及びその製造方法を提供することにある。
【００１０】
【課題を解決するための手段】
上記目的を達成するため、この発明による空気入りタイヤ用未加硫ゴム部材は、幅方向に厚ゲージ領域と薄ゲージ領域とを合せもつ押出し裁断した長尺の帯状空気入りタイヤ用未加硫ゴム部材において、
同一配合組成になる未加硫ゴムの押出し条件を相互に違えることによりムーニー粘度に差を付した２種類以上のゴム材料を同時に押出し合体させて成る上記ゴム部材が、最も高いムーニー粘度値を有するゴム材料を厚ゲージ領域に位置させ、かつ最も低いムーニー粘度値を有するゴム材料を少なくとも薄ゲージ領域に位置させて成り、
これにより所定長さに切断して冷却した合体ゴム部材は、薄ゲージ領域の端縁長さが厚ゲージ領域のそれに比しより長い寸度を有することを特徴とする。
【００１１】
またこの発明による空気入りタイヤ用未加硫部材の製造方法は、幅方向に厚ゲージ領域と薄ゲージ領域とを合せもつ長尺の帯状空気入りタイヤ用未加硫ゴム部材を押出機により押出し成形するにあたり、
２基以上の押出機を押出金型近傍にて合体化した複合形押出機を用い、各押出機をそれぞれ異なる押出条件で稼働させ、この稼働の下で同一配合組成になる未加硫ゴムを各押出機毎に異なるムーニー粘度として合体させて押出し成形し、この成形形態を、最も高いムーニー粘度値を有するゴム材料を厚ゲージ領域に位置させ、かつ最も低いムーニー粘度値を有するゴム材料を少なくとも薄ゲージ領域に位置させるものとし、
これにより押出し成形直後における合体ゴム部材を長手方向に所定長さで切断して冷却したとき、薄ゲージ領域の端縁長さが厚ゲージ領域の端縁長さを上回る合体ゴム部材を得ることを特徴とする。
【００１２】
先に述べたこの二つの発明を実施するにあたり、上記合体ゴム部材のうち最も高いムーニー粘度を有するゴムの該粘度値を指数１００であらわすとき、残余ゴムのムーニー粘度値指数が８０以下であることが望ましい。
【００１３】
【作用】
従来、幅方向に厚ゲージ領域と薄ゲージ領域とを合わせもつ長尺の帯状ゴム部材を押出機から押出した直後に所定長さで切断したゴム部材は、それ自体が高温度であること、そして押出機の押出口に設けた金型を未加硫ゴムが強力な押圧力下で通過する際、厚ゲージ領域の開口度合いに比し薄ゲージ領域の開口度合いがより狭いため、薄ゲージ領域におけるゴム流動に対する抵抗力がより大きくなることは不可避である。
【００１４】
このことは、より大きな抵抗力の作用を経た薄ゲージ領域における残留応力の大きさが厚ゲージのそれに比しより大きいことを示唆していることに外ならない。この残留応力は言うまでもなく収縮力に相当し、ゴム部材が高温度のときは応力緩和効果のためさほど大きな収縮力をもたらすことはなく、常温付近まで温度が低下したとき大きな収縮力が作用する上、ゲージが小さくなるほど大きな収縮応力となるため、薄ゲージ領域の端縁長さが厚ゲージ領域のそれに比しより短くなり、その結果図２（ｂ）で示したゴム部材１１′のように先端部の大きな倒れ込み現象が生じることを見出した。
【００１５】
そこでこの発明では、厚ゲージ領域を占めるゴム材料のムーニー粘度値に比し、少なくとも薄ゲージ領域を占めるゴム材料のムーニー粘度値をより小さくして、複合形押出機（デュアルチューバ又はトリプルチューバなど）から合体ゴム部材として押出すことにより、押出金型を通過する際の薄ゲージ領域におけるゴム流動性を増して、不可避的にもたらされる薄ゲージ領域ゴム材料の残留応力をより小さくすることが可能となる。それ故、切断後に常温まで冷却した薄ゲージ領域ゴムの収縮量を厚ゲージ領域ゴムのそれに比しより小さくすることができ、その結果合体ゴム部材のうち薄ゲージ領域の端縁長さを厚ゲージ領域の端縁長さに比しより長くすることが可能となる。
【００１６】
上記の合体ゴム部材材料は同一配合組成になることが必要であり、たとえ同一配合組成ゴムであっても押出し条件を変えることにより、例えば複合形押出機における各押出機のスクリュ回転数を変えること、これはとりもなおさずゴムに加えるせん断力及びせん断エネルギを変えて押出金型近傍でのそれぞれのゴム温度を変えることであり、その結果各押出機から押出されるゴムのムーニー粘度値に差を付すことが可能となる。また押出機に供給するに先立ち、同一配合組成ゴムに対しゴム練り条件を変えておけば上記効果をさらに助勢することができる。
【００１７】
合体ゴム部材の同一配合組成になるゴムのムーニー粘度値を指数であらわすとき、最も高いムーニー粘度をもつゴムの指数を１００とし残余ゴムの指数を８０以下とすれば、上述した効果はより一層顕著なものとなる。
【００１８】
上記のようにして得られた合体ゴム部材をビードコア７にプリセットした場合、タイヤで半径方向外側となる先細り部分、すなわち薄ゲージ領域部分はもはや図２（ｂ）に示すような倒れ込み現象を呈することはなく、従って製品タイヤとなった際の製造不良を根絶することが可能となる。また加硫成形を経た後の合体ゴム部材は一体としてほぼ同一物性、同一性能を発揮するので、タイヤとしての性能及び耐久性共に劣化のうれいもない。
【００１９】
なお上述した厚ゲージ領域及び薄ゲージ領域は、合体ゴム部材の断面にて、最も長い辺と、最大ゲージを示す頂点から最長辺にに下ろした垂線との交点から、前述の先き細り端までの長さの中点を通る最長辺の垂直線を境とする領域と定義する。また厚ゲージ領域内に薄ゲージ領域を占めるゴム材料が入り込むことを可とする。
【００２０】
【実施例】
空気入りタイヤのうちの乗用車用ラジアルプライタイヤで、サイズが１８５／７０Ｒ１４のビード部補強ゴムとしてのビードフィラーゴムに、図１（ａ）に斜視図として示す同一配合組成になる合体押出し未加硫ゴム部材１０を適用した。
【００２１】
図１（ａ）において、合体ゴム部材１０は図に示す矢印Ａの向きに押出し成形したものであり、元来タイヤのリム径に相応するビードコア外周の長さとほぼ同等の長さを有する長尺ものであるが、中間部分を省略図示した。図の下に示す辺ｌｍ （約４５ｍｍ）、ｌｎ （約４３ｍｍ）、ｌｂ （約６ｍｍ）にて囲まれるほぼ三角形部分は押出し成形時の切断面である。
【００２２】
この三角形部分の中に示す線ＢＬは、最も高いムーニー粘度をもつゴム領域と最も低いムーニー粘度をもつゴム領域との境界線（ゴム部材１０としては境界面）をあらわす。図に示す例の切断面での最長辺は辺ｌｍ であり、最大ゲージを示す頂点Ｐから辺ｌｍ に下ろした垂線と辺ｌｍ とを交点Ｏで示し、交点Ｏと先細り端Ｑとのほぼ中点に立てた辺ｌｍ の垂直線ｌを境とし、図１（ａ）でみて垂直線ｌの左側が厚ゲージ領域、右側が薄ゲージ領域である。なお辺ｌｂ 側の表面をビードコアの外周面に粘着させる。
【００２３】
この実施例での合体ゴム部材１０は６ｉｎ（インチ）×６ｉｎのデュアルチューバにより押出し成形したものであり、成形形態は主として厚ゲージ領域に最も高いムーニー粘度のゴム１０−１を配置し、薄ゲージ領域には、厚ゲージ領域に跨がり最も低いムーニー粘度のゴム１０−２を配置した。この時デュアルチューバそれぞれのスクリュ回転数を変えることにより押出し条件に差を付した。すなわちゴム１０−１での回転数とゴム１０−２での回転数との比を６：４とした。そのときムーニー粘度値はゴム１０−１を１００とする指数であらわしてゴム１０−２の指数は７５であった。
【００２４】
実施例と従来例とを下記項目（１）〜（３）にて比較評価した。
（１）評価対象本数；実施例４００本、従来例４００本。
（２）評価方法その一；図１（ａ）に示すビードコア側端縁長さＬ１ を指数１００としたとき、先細り端縁長さＬ２ の指数値（大なるほど良い）。
（３）評価方法その二；ゴム部材１０、１１′によるところの製造不良（主としてエア入り）発生率（％）。
【００２５】
評価結果は、まず上記第（２）項において、実施例の端縁長さＬ２ が１１０〜１１５であったのに対し、従来例では８０〜８５に止まり、第（３）項では実施例が０％であり、従来例は１５％に及んだ。このことから実施例は従来例に比し製造不良に関し格段に優れたビード部補強用未加硫ゴム部材であるのは明らかである。
【００２６】
最後に上述した実施例を適用するタイヤを図１（ｂ）に基づき説明する。図１（ｂ）は先に述べたラジアルプライタイヤの右半断面であり、タイヤ赤道面Ｅを挟んで両側対称である。図に示す符号において１はタイヤ、２はトレッド部、３はサイドウォール部、４はビード部であり、カーカス５はこれらトレッド部２、サイドウォール部３及びビード部４を補強し、さらにベルト６はトレッド部２を強化する。カーカス５はビードコア７ａの周りをタイヤ１の内側から外側に向け巻上げ、ビードフィラ１０ａ（上記ゴム部材、但し加硫成形後であるため添字ａを付した。ビードコア７ａも同じ）の一部又は全体を覆う。
【００２７】
【発明の効果】
この発明によれば、従来製造不良をもたらす主因となっていたビード部補強用ゴム部材の先細り先端部の倒れ込みを他の不具合を伴うことなく有利に改善することができ、これによりエア入りなどのタイヤ製造不良発生を回避することが可能な空気入りタイヤ用未加硫ゴム部材及びその製造方法を提供することができる。
【図面の簡単な説明】
【図１】この発明によるビードフィラーゴム部材の斜視図及び該部材を適用したタイヤの右半断面図である。
【図２】従来のビードフィラーゴム部材をビードコア部材にプリセットした断面図である。
【符号の説明】
１ タイヤ
２ トレッド部
３ サイドウォール部
４ ビード部
５ カーカス
６ ベルト
７ ビードコア部材
７ａ ビードコア
１０ ビードフィラーゴム部材
１０−１ 最も高いムーニー粘度をもつゴム
１０−２ 最も低いムーニー粘度をもつゴム
１０ａ ビードフィラーゴム
Ｌ１ ビードフィラーゴム部材のビードコア側端縁長さ
Ｌ２ ビードフィラーゴム部材の先細り先端の端縁長さ
ＢＬ ムーニー粘度が異なるゴム相互の境界線[0001]
[Industrial application fields]
TECHNICAL FIELD The present invention relates to an extruded unvulcanized rubber member applied to a pneumatic tire and a method for manufacturing the same, and in particular, suppressing generation of scrap of a product tire due to a manufacturing failure in a manufacturing process of a pneumatic tire based on a failure of the rubber member, and scrap TECHNICAL FIELD The present invention relates to an unvulcanized rubber member for a pneumatic tire that is effective for reducing industrial waste due to conversion and a manufacturing method thereof.
[0002]
[Prior art]
Among the various assembled members of the pneumatic tire, the unvulcanized rubber member can be roughly classified into a sheet member having a uniform gauge rolled by a roll such as a calender roll and an extruded member by an extruder. Among these, the latter rubber member generally changes in gauge in the width direction, and is divided into two regions which can be called a thick gauge region and a thin gauge region.
[0003]
In particular, in the case of a radial ply tire among pneumatic tires, a bead filler rubber or a stiffener rubber that has a substantially triangular cross-section extending from the bead core toward the outer side in the tire radial direction in order to give a desired rigidity to the bead portion. It is customary to apply a part reinforcing rubber member.
[0004]
This reinforced rubber member is used separately depending on the type of tire and the required characteristics, in the case of a single body of rubber material having the same compounding composition and in the case of a composite of rubber material having a different compounding composition. It is customary to prepare an unvulcanized rubber member by extrusion molding using an extruder.
[0005]
[Problems to be solved by the invention]
When the above-mentioned reinforcing rubber member is a single rubber material having the same compounding composition, or even in the case of the same compounding composition rubber material in the composite, when the cross-sectional area exceeds the extrusion capacity of the extruder to be applied, so-called Extrusion molding with a composite extruder (dual tuba) is rarely performed, but it is usually performed by extrusion with a single tuba. Hereinafter, for the convenience of explanation, a case where the reinforcing rubber member has the same composition will be described.
[0006]
In order to increase the productivity of tire molding as much as possible for the convenience of production, that is, a bead portion reinforced unvulcanized rubber member extruded as shown in a cross section in FIG. 11 needs to be bonded to the
[0007]
On the other hand, the rubber member 11 is not formed by extrusion molding for each required length, but is continuously extruded by an amount corresponding to a very large number, and thus obtained by sequentially cutting to a predetermined length immediately after extrusion. It is done. At the time of this cutting, of course, both end cut surfaces form surfaces parallel to each other.
[0008]
When the end face of the rubber member 11 on the side of the thickness gauge region is bonded to the outer peripheral surface of the
[0009]
Accordingly, an object of the present invention is to advantageously improve the above-described collapse without causing other problems, and to avoid occurrence of defective tire production such as pneumatic, and a method for producing the same. Is to provide.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, an unvulcanized rubber member for a pneumatic tire according to the present invention is an unvulcanized rubber for a long strip-shaped pneumatic tire which is extruded and cut having both a thick gauge region and a thin gauge region in the width direction. In the member,
The above rubber member formed by simultaneously extruding and combining two or more kinds of rubber materials having different Mooney viscosities by changing the extrusion conditions of unvulcanized rubber having the same compounding composition has the highest Mooney viscosity value. The rubber material is located in the thick gauge region, and the rubber material having the lowest Mooney viscosity value is located at least in the thin gauge region;
Thus, the united rubber member cut to a predetermined length and cooled is characterized in that the edge length of the thin gauge region is longer than that of the thick gauge region.
[0011]
The method for producing an unvulcanized member for a pneumatic tire according to the present invention is a method of extruding an elongated unvulcanized rubber member for a pneumatic tire having a thick gauge region and a thin gauge region in the width direction by an extruder. In doing
Using a compound extruder in which two or more extruders are combined in the vicinity of the extrusion mold, each extruder is operated under different extrusion conditions, and under this operation, unvulcanized rubber having the same composition is obtained. The different Mooney viscosities for each of the extruders are combined and extruded, and this molding is performed by placing the rubber material having the highest Mooney viscosity value in the thick gauge region and at least the rubber material having the lowest Mooney viscosity value. Shall be located in the thin gauge area,
Thus, when the united rubber member immediately after extrusion molding is cut by a predetermined length in the longitudinal direction and cooled, the united rubber member is obtained in which the edge length of the thin gauge region exceeds the edge length of the thick gauge region. Features.
[0012]
In carrying out these two inventions described above, when the viscosity value of the rubber having the highest Mooney viscosity among the combined rubber members is represented by an index 100, the Mooney viscosity value index of the remaining rubber is 80 or less. Is desirable.
[0013]
[Action]
Conventionally, a rubber member cut at a predetermined length immediately after a long strip rubber member having both a thick gauge region and a thin gauge region in the width direction is extruded from an extruder has a high temperature itself, and When the unvulcanized rubber passes through the mold provided at the extrusion port of the extruder under a strong pressing force, the opening degree of the thin gauge area is narrower than the opening degree of the thick gauge area. It is inevitable that the resistance to rubber flow is greater.
[0014]
This is nothing less than suggesting that the magnitude of the residual stress in the thin gauge region that has undergone the action of a greater resistance is greater than that of the thick gauge. Needless to say, this residual stress corresponds to a shrinkage force. When the rubber member is at a high temperature, it does not cause a large shrinkage force due to the stress relaxation effect, and a large shrinkage force acts when the temperature drops to near room temperature. Since the shrinkage stress becomes larger as the gauge becomes smaller, the edge length of the thin gauge region becomes shorter than that of the thick gauge region. As a result, the tip of the rubber member 11 ′ shown in FIG. It has been found that a large falling phenomenon occurs.
[0015]
Accordingly, in the present invention, the Mooney viscosity value of the rubber material occupying at least the thin gauge region is made smaller than the Mooney viscosity value of the rubber material occupying the thick gauge region, and a composite type extruder (such as a dual tuba or triple tuba) is used. By extruding as a coalesced rubber member, it is possible to increase the rubber fluidity in the thin gauge region when passing through the extrusion die, and to reduce the residual stress of the thin gauge region rubber material inevitably brought Become. Therefore, the shrinkage amount of the thin gauge area rubber cooled to room temperature after cutting can be made smaller than that of the thick gauge area rubber, and as a result, the edge length of the thin gauge area of the united rubber member can be set to the thickness gauge. It becomes possible to make it longer than the edge length of the region.
[0016]
The united rubber member material must have the same compounding composition. Even if the compounding compound rubber is the same, it is possible to change the screw rotation speed of each extruder in a compound extruder, for example, by changing the extrusion conditions. This is, of course, changing the shear force and shear energy applied to the rubber to change the temperature of each rubber near the extrusion mold, resulting in a difference in the Mooney viscosity value of the rubber extruded from each extruder. Can be attached. Further, if the rubber kneading conditions are changed for the same compounded rubber prior to feeding to the extruder, the above effect can be further enhanced.
[0017]
When the Mooney viscosity value of the rubber having the same composition of the combined rubber member is expressed as an index, the effect described above becomes even more remarkable if the index of the rubber having the highest Mooney viscosity is 100 and the index of the remaining rubber is 80 or less. It will be something.
[0018]
When the united rubber member obtained as described above is preset in the
[0019]
The above-mentioned thick gauge region and thin gauge region are from the intersection of the longest side and the perpendicular line extending from the vertex indicating the maximum gauge to the longest side in the cross section of the united rubber member, to the tapered end described above. Is defined as the area bounded by the longest vertical line that passes through the midpoint of the length. Further, it is possible to allow a rubber material occupying the thin gauge region to enter the thick gauge region.
[0020]
【Example】
Of pneumatic tires, radial ply tires for passenger cars, union vulcanized unmodified vulcanized with the same compound composition shown in the perspective view of FIG. 1 (a), to bead filler rubber as size 185 / 70R14 bead portion reinforcing rubber The
[0021]
In FIG. 1 (a), the
[0022]
A line BL shown in the triangular portion represents a boundary line (boundary surface as the rubber member 10) between the rubber region having the highest Mooney viscosity and the rubber region having the lowest Mooney viscosity. The longest side of the cut surface of the example shown in the figure is the side lm, the perpendicular line extending from the vertex P indicating the maximum gauge to the side lm and the side lm are indicated by the intersection point O, and the middle of the intersection point O and the tapered end Q With the vertical line 1 of the side lm standing at a point as a boundary, the left side of the vertical line 1 is a thick gauge region and the right side is a thin gauge region as seen in FIG. The surface on the side lb side is adhered to the outer peripheral surface of the bead core.
[0023]
The
[0024]
Examples and conventional examples were compared and evaluated in the following items (1) to (3).
(1) Number of evaluation objects: 400 examples and 400 conventional examples.
(2) Evaluation Methods In one thereof; when the bead core side edge length L 1 shown in FIG. 1 (a) and index 100, tapered edge length L 2 of the index value (large indeed good).
(3) Evaluation method No. 2; production rate (mainly air-filled) occurrence rate (%) due to the
[0025]
The evaluation results, first, in the subsection (2), whereas the edge length L 2 of Example was 110 to 115, in the conventional example stops at 80-85, in the paragraph (3) Example Was 0%, and the conventional example reached 15%. From this, it is clear that the embodiment is an unvulcanized rubber member for reinforcing the bead part, which is remarkably superior in terms of manufacturing failure compared to the conventional example.
[0026]
Finally, a tire to which the above-described embodiment is applied will be described with reference to FIG. FIG. 1B is a right half section of the radial ply tire described above, and is symmetric on both sides with respect to the tire equatorial plane E. FIG. In the code | symbol shown in the figure, 1 is a tire, 2 is a tread part, 3 is a side wall part, 4 is a bead part, Carcass 5 reinforces these
[0027]
【The invention's effect】
According to the present invention, it is possible to advantageously improve the collapse of the tapered tip end portion of the bead portion reinforcing rubber member, which has been a main cause of manufacturing defects in the past, without causing other problems, and thereby, for example, entering air It is possible to provide an unvulcanized rubber member for a pneumatic tire and a method for manufacturing the same that can avoid the occurrence of tire manufacturing defects.
[Brief description of the drawings]
FIG. 1 is a perspective view of a bead filler rubber member according to the present invention and a right half sectional view of a tire to which the member is applied.
FIG. 2 is a cross-sectional view in which a conventional bead filler rubber member is preset in a bead core member.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1
Claims (3)
同一配合組成になる未加硫ゴムの押出し条件を相互に違えることによりムーニー粘度に差を付した２種類以上のゴム材料を同時に押出し合体させて成る上記ゴム部材が、最も高いムーニー粘度値を有するゴム材料を厚ゲージ領域に位置させ、かつ最も低いムーニー粘度値を有するゴム材料を少なくとも薄ゲージ領域に位置させて成り、
これにより所定長さに切断して冷却した合体ゴム部材は、薄ゲージ領域の端縁長さが厚ゲージ領域のそれに比しより長い寸度を有することを特徴とする空気入りタイヤ用未加硫ゴム部材。In an unvulcanized rubber member for a long belt-like pneumatic tire that has been cut by extrusion and has both a thick gauge region and a thin gauge region in the width direction,
The above rubber member formed by simultaneously extruding and combining two or more kinds of rubber materials having different Mooney viscosities by changing the extrusion conditions of unvulcanized rubber having the same blending composition has the highest Mooney viscosity value. The rubber material is located in the thick gauge region, and the rubber material having the lowest Mooney viscosity value is located at least in the thin gauge region;
The unionized rubber tire for a pneumatic tire is characterized in that the united rubber member cut to a predetermined length and cooled has an edge length in the thin gauge region longer than that in the thick gauge region. Rubber member.
２基以上の押出機を押出金型近傍にて合体化した複合形押出機を用い、各押出機をそれぞれ異なる押出条件で稼働させ、この稼働の下で同一配合組成になる未加硫ゴムを各押出機毎に異なるムーニー粘度として合体させて押出し成形し、この成形形態を、最も高いムーニー粘度値を有するゴム材料を厚ゲージ領域に位置させ、かつ最も低いムーニー粘度値を有するゴム材料を少なくとも薄ゲージ領域に位置させるものとし、
これにより押出し成形直後における合体ゴム部材を長手方向に所定長さで切断して冷却したとき、薄ゲージ領域の端縁長さが厚ゲージ領域の端縁長さを上回る合体ゴム部材を得ることを特徴とする空気入りタイヤ用未加硫ゴム部材の製造方法。When extruding an unvulcanized rubber member for a long belt-like pneumatic tire having a thick gauge region and a thin gauge region in the width direction by an extruder,
Using a compound extruder in which two or more extruders are combined in the vicinity of the extrusion mold, each extruder is operated under different extrusion conditions, and under this operation, an unvulcanized rubber having the same composition is obtained. The different Mooney viscosities for each of the extruders are combined and extruded, and this molding form is such that the rubber material having the highest Mooney viscosity value is positioned in the thick gauge region and the rubber material having the lowest Mooney viscosity value is at least Shall be located in the thin gauge area,
Thus, when the united rubber member immediately after extrusion molding is cut by a predetermined length in the longitudinal direction and cooled, it is possible to obtain a united rubber member in which the edge length of the thin gauge region exceeds the edge length of the thick gauge region A method for producing an unvulcanized rubber member for a pneumatic tire.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP01238395A JP3616151B2 (en) | 1995-01-30 | 1995-01-30 | Unvulcanized rubber member for pneumatic tire and method for producing the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP01238395A JP3616151B2 (en) | 1995-01-30 | 1995-01-30 | Unvulcanized rubber member for pneumatic tire and method for producing the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08197638A JPH08197638A (en) | 1996-08-06 |
| JP3616151B2 true JP3616151B2 (en) | 2005-02-02 |
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| Application Number | Title | Priority Date | Filing Date |
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| JP01238395A Expired - Fee Related JP3616151B2 (en) | 1995-01-30 | 1995-01-30 | Unvulcanized rubber member for pneumatic tire and method for producing the same |
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| JP (1) | JP3616151B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6081153B2 (en) * | 2012-11-13 | 2017-02-15 | 東洋ゴム工業株式会社 | Pneumatic tire manufacturing method and pneumatic tire |
| US10583696B2 (en) | 2014-12-09 | 2020-03-10 | Bridgestone Americas Tire Operations, Llc | Tire with bead regions having multiple bead fillers |
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1995
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| JPH08197638A (en) | 1996-08-06 |
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